Apparatus for treating sound tracks of color film



June 17, 1952 MlLLER 2,600,565

APPARATUS FOR TREATING SOUND TRACKS OF COLOR FILM Filed May 28, 1949 3 Sheets-Sheet 1 BY WQW ATTORN EY June 17, 1952 A. J. MILLER 2,600,555

APPARATUS FOR TREATING SOUND TRACKS OF COL-OR FILM Filed May 28, 1949 3 Sheets-Sheet 2 INVENTOR ATTORNEY June 17, 1952 MILLER 2,600,565

APPARATUS FOR TREATING SOUND TRACKS OF COLOR FILM ATTORN EY Patented June 17, 1952 APPARATUS FOR TREATING SOUND TRACKS OF COLOR FILM Arthur J. Miller, Teaneck, N. J assignor to Republic Pictures Corporation, New York, N. Y., a corporation of New York Application May 28, 1949, Serial No. 96,104

Claims.

This invention relates to apparatus for treating colored motion picture film so as to obtain a sound track having greater contrast than that produced by using only the dyes that make the colored images on the film.

A dye sound track is not opaque to infra red light, and because of this the sound reproduction obtained from such sound tracks is not as quiet as the reproduction obtained with sound tracks having their opaque portions made of a silver salt, or some other metallic salt, which is capable of blocking infra red rays.

It is an object of this invention to provide apparatus for treating a sound track of a motion picture film independently of the picture images. The treatment may include the application of de veloper to the sound track before or after the developing of the picture images; it may include the application of a coating of lacquer to the sound track to protect it from contact with certain of the chemicals used in processing the image area of the film; or it may include the selective application of some other liquid to a longitudinal zone of the film with a sharp line of limitation separating such zone from the remainder of the film.

It is a more specific object of this invention to provide apparatus for developing a metallic image along the sound track of colored film without interfering with the usual processing of that portion of the film on which the picture images are formed With dyes. The invention preferably employs the metal of the original emulsion, with certain necessary chemical treatments, to ob tain the final sound track.

Another object of the invention is to provide apparatus by which a sound track can be developed, to produce a metallic salt image, preferably as a continuous operation with the development of the dye images on the picture portion of the film.

Other features of the invention relate to apparatus for applying a developer to the sound track of a film with highly accurate control of the application of the developer so as to maintain a developed area of uniform width along the sound track on only one face of the film. Other features relate to treatment of the film to prevent spread of the developer on the Wet faces of the film during its processing, and to treating of the film without scratching it and While the film is moving rapidly through the successive steps of the developing process.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views,

Figure 1 is a diagrammatic assembly view showing apparatus for developing sound tracks of colored films in accordance with this invention.

Figure 2 is a greatly enlarged view of the apparatus shown in Figure l for applying developer to the sound track.

Figure 3 is a sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a diagrammatic perspective view of the developer station of the apparatus shown in Figure 1.

Figures 5 and 6 are views taken on the lines 5-5 and 6-B respectively, of Figure 2, illustrating the cross slides for adjusting the applicator wheel with respect to the film.

Figure 1 shows the different steps through which a film [0 passes when developing the sound track in accordance with this invention. After passing through the usual process of development in a color developer, the film passes through a fixing solution which removes the undeveloped silver. The film It then passes over a guide roller II and is led down into a washing tank 12. The film passes around a group of guide rollers l4 and I5 which provide a number of loops of the film in the tank I2 so that the film is immersed in the water for a substantial period of time even though the film is moving at fairly high lineal speed. Hypo remaining on the film is washed out in the tank 12.

The film passes from the washing tank l2 over guide rollers ll, to a tank l9 containing a, bleaching solution that converts the metallic silver remaining in emulsion on the film back to a silver salt. Potassium ferricyanide and potassium bromide are suitable chemicals for the bleaching solution. This step of bleaching is conventional in color film work.

The film It then passes from tank I9 over guide rollers 29 to another washing tank 2| containing water. In the tank 2| the film passes over rows of guide rollers as in the case of tank I 2, in order to thoroughly wash all bleaching solution from the film.

In order to prevent water on the film from causing uneven spreading of the developer that is applied to the sound track beyond the tank 2|, the film is passed through a compressed air squeegee 23. Air jets from nozzles 24 are directed against both surfaces of the film in the direction opposite to the film movement; and these air jets blow all loose water from the film.

3 The only water remaining on the film surfaces is the water that has been soaked up by the film. This water is not objectionable because it is evenly distributed, and i does not cause any uncontrolled spread or" the subsequently applied developer.

The film it passes from the squeegee 23 to guide rollers 22 and 28 at one end of the developer station. In Figure l, the developer station is indicated generally by the reference charactor 27. lhe construction and operation of the developer station will be explained in connection with Figures 2 to 7. For the present, it is sumcient to understand that a developer solution is applied to the sound track, and only the sound track, at the developer station 21.

The film travels over a guide roller 29 at the delivery end of the developer station 2?. The developer is applied to only one side of the film and the side to which the developer is applied is on the outside of the curve as the film passes around the guide roller 2'3. This prevents the developer from being spread by contact with the surface of the guide roller 29.

A Water squeegee 32 is located along the course of the film ill at a substantial distance from the developer station 2?. The distance of this water squeegee from the developer station must be coordinated with the speed at which the film is moving so that sufficient time for developing the sound track will elapse during the passage of the film from the developer station 2! to the water squeegee 3E. Stron streams of water are projected from headers 34 of the water squeegee and these streams or" Water wash the sound track thoroughly and rinse the developer from the side of the sound track to which it was applied at the developer station.

In the preferred embodiment of this invention, the developer is applied to only one surface of the sound track. It could be applied to both, but it is unnecessary to develop a, metallic salt image on both sides of the sound track and there are disadvantages in attempting to do so. One disadvantage is that a uniform control of the developer is more diflicult when it is applied to the side of the film which must contact the guide rollers. In developing one side only, however, it is very important to prevent any of the developer from creeping around the edge of the film and spreading irregularly over the other side of the sound track. Such an uneven developing of the rearward side of the sound track would produce a noisy track.

Below the water squeegee 32, the film it? passes into a tank 33 filled with water. While passing through this tank 35, the film ii? is washed for a long enough period to remove any developer which might remain absorbed in the emulsion of the sound track. The water in the tank 33 is agitated by a stream introduced through a nozzle 38 near the region where the film l first enters the water in the tank 36. This agitation prevents the Water which is first encountered by the film from accumulating sufiicient developer to create a local zone where some further developing of the sound track may occur. By agitating the water, the developer removed from the film becomes so diluted that it can have no further effect on the sound track.

The film iii passes from the washing tank 33 over guide rollers 39 to a tank 29 containing fixing solution. The film passes around successive guide rollers 42 in the tank 40, there being enough of these guide rollers to form loops of film providing sufiicient length to keep the film in the fixing solution of the tank as long as necessary at the speed at which the film is moving.

After passing through the tank id, the film travels over guide rollers 44 to a final washing tank 5 containing water. Guide rollers 48 in the tank provide the necessary number of loops for the film IO; and there is another guide roller 59 over which the fihn passes from the final washing tank 45 to a dryer.

Figure 2 shows the manner in which developer is applied to the sound track of the film 10 at the developer station 27. The developer is preferabl applied to the film at a region at which the film bends around a guide roller with the film under some tension. This insures a uniform clearance between the the film and the developer applicator since the tensioned film on the guide roller is held firmly against any movement transverse of its direction of travel.

The film it) passes around a guide roller which is secured to the lower end or a shaft 55 that turns in ball bearings 51 carried by a fixed bracket Guide roller 55 is is constructed so that the opposite sides of the film contact with cylindrical surfaces 63 0f the roller but the cylindrical surface of the roller between these p ipheral surfaces is of reduced diameter so that there is no support for the film directly behind the sound track 62.

An applicator disk 64 is rotated about an axis at an acute angle to the axis of the guide roller The upper part of the applicator disk 54 touches, or almost touches, the sound track of the film passing around the guide roller 55; and the lower part of the applicator disk 64 is in a tray 68 below the liquid level 83 of a developer solution contained in the tray. As the applicator disk 64 rotates, it carries developer from the tray 66 upward into contact with the sound track of the film [0.

The film ls can be passed around a guide roll 55 that turns about a vertical axis, but in such a case the plane of the sound track is vertical and a maximum gravitational effect tends to make the developer run off the face of the film.

n the other hand, it is not desirable to have the plane or" the film horizontal because in such a case there is danger that the developer will spread beyond the blend line and over a part of the picture areas of the film. Best results are obtained by having the plane of the film, at the time of application of the developer, at an acute angle to the horizontal. Experience has shown that an angle of 35 gives very good results.

Best results have been obtained by having the face or" the applicator disk 64 constructed so that it is closer to the film ii) at the upper edge of the sound track, that is, at the blend line between the picture and the sound track when the lm I0 is oriented as shown in Figure 2.

By having the portion of the applicator disk 54 which is nearest the film made with a pointed edge, an extremely accurate control is obtained for the location of the upper line of the dcveloper on the film. This makes it possible to maintain a substantially straight line along the side of the sound track that blends with the picture area of the film. The relation of the disk 64 to the film is shown on an enlarged scale in Figure 3. The face of the disk 64 confronting the sound track is preferably of substantially the same width as the sound track. Although the face of the disk 64 is preferably closer to the film at the upper end of the sound track, the divergence of the face of the disk 65 from the surface of the sound track transversely of the track is at a small angle and the coating of deeloper on the disk is of sufficient thickness and has sufficient surface tension so that the disk applies developer to the sound track across the full width of the track. In adjusting the disk 65 with respect to the sound track on the film, the sharp edge of the disc must be located slightly inward from the blend line so that the coating of developer on the disk will extend exactly to the blend line which separates the sound track from the picture areas.

The apparatus is preferably adjusted so that the applicator disk 6d does not touch the film ill, but the clearance is small enough so that when there is developer on the applicator disk, this developer extends across the clearance between the disk 6 and the film Iii. The thickness of the coating of the developer on the applicator disk 64 depends upon several different factors including the viscosity of th developer, the amount of developer on the disk, and the speed with which the disk is rotated. A higher speed of rotation increases the centrifugal force and this increases the thickness of the coating up to the value at which the centrifugal force becomes sufiicient to throw the developer from the disk.

Referring again to Figure 2, the concentricity of the guide roller 55 should be as accurate as possible, but perfect concentricity is extremely difficult to obtain in manufacturing, and allowance is made for eccentricity by not having the surface of the roller 55 directly behind the sound track 62 spaced from the film. With such a construction, the film Ill can yield slightly if it comes into actual contact with the applicator disk t l. In the ordinary operation of the apparatus, however, the clearance between the applicator disk 64 and the film If! not only provides a better control of the width of film area covered by the developer but it also insures against any scratching of the film by the applicator disk 64.

The amount of developer carried by the applicator disk E4 is maintained substantially constant by keeping th liquid level 68 uniform, by maintaining a uniform speed of rotation of the disk 84 and by wiping excess developer from the disk on the side that is moving upward from the tray 66 towards the roller 55.

The liquid level in the tray 66 is maintained substantially uniform by having a reservoir H which supplies additional developer to the tray es as is needed. This reservoir H comprises an inverted bottle from which liquid will flow only when air can enter the mouth of the bottle. Whenever the liquid level drops below the mouth of the bottle sufficiently to permit air to enter the bottle, some additional liquid flows from the bottle into the tray '66.

Figure 3 shows a scraper 13 for removing excess liquid from the applicator disk 64 on the side of the wheel that is moving upward. This scraper i3 is shaped so as to remove liquid from the sides of the disk, but not from the pointed peripheral face of the disk. This feature allows the full angular movement of the disk 64, from the liquid level to the film, within which the liquid bead on the periphery of the applicator disk can take shape. Removal of liquid from the sides of the disk, however, prevents continued growth of the bead as the disk continues to rotate and also keeps minor variations in the liquid level from '6 affecting the amount of developer applied to the film.

Referring again to Figure 2, the applicator disk 64 is secured to one end of a shaft 16 supported by bearings in a bracket 11 and provided with thrust bearings 78 for preventing endwise displacement of the shaft 16. The bracket 11 is secured in place on a slide 80 by a clamping screw SI and dowel pin 82. Th screw 8| extends through an arcuate slot 83 in the bracket 11, so that the bracket 11 can swing about the axis of the dowel pin 82 as a center when the screw 8! is loosened.

The slide 8% is adjustable along different coordinates as will be explained in connection with Figures 5 and 6. For the present it is sufficient to understand that the slide 89, with the bracket i I and applicator disk 64, can be raised and lowered by rotating a knob 84; and can be moved toward and from the axis of the guide roller 55 by rotating a knob 85. These adjustments are for the purpose of accurately controlling the exact area of the film to which the liquid developer is applied by the applicator disk 64.

The shaft H5 is rotated by an electric motor 8? mounted on a frame 88 which is the same frame by which the bracket 58 is supported, and the sam frame from which the slide 80 is ultimately supported. The motor 8'! drives an output shaft 95] through reduction gearing Sl' attached to the end of the motor housing. The output shaft 99 is connected with the shaft 16 of the applicator disk by a universal joint 92 and a telescoping connection 93 between one end of the universal joint $2 and the output shaft of the reduction gearing 9| Figure 4 is a diagrammatic view showing the way in which two successive applications of developer are made to the sound track at the developer station. By making two applications, more developer can be applied without danger of having the band of developer so heavy that it runs down the film. The principal danger in having the developer run down over the lower edge of the film is that some of the developer will travel through the sprocket openings and creep over the emulsion on the back surface of the film with the result that there will he a development of the rearward surface of the sound track at the places where th developer travels through the sprocket openings.

The second application of developer to the sound track is made by apparatus which is preferably identical with that already described in connection with Figure 2. This apparatus is indicated in Figure 4 by the same reference characters as the apparatus for making the first application of developer, but with a prime appended to the reference characters.

The only difference in the application of develope-r by the disk 64 and the other disk 64', is that a more viscous solution is app-lied by the disk The developer in the tray 68 preferably contains some starch or other thickening material. Sodium sulfide is a suitable developer. In the second tray 66 a water solution of sodium sulfide without the addition of starch or other thickener is employed. Developer may be applied at more than two stations. Any number of stations can be used. Thinner developer solutions require more applications in order to obtain complete development.

Figure 4 also shows the water squeegee 82 and the orientation of the nozzles of the headers 3 These nozzles are directed and located in position to wash the developer from the sound track in a direction away from the picture areas of the film. In this way any possible reaction between the developer and the picture areas is avoided.

application of developer to the sound track or the bleaching step and as a continuous pration with the processing of the picture areas f the film is one embodiment of the invention. will be understood that the developer can be lied to the sound track to develop the sound it with a metallic image before the picture ges are developed in a color developer. The feature of the invention by which a coat of liquid can be applied to a longitudinal zone, with a sharp line of separation from the t adjacent zone, c n be employed in other of the process for the other film. The necessary time allowniade for the applied liquid to in some cases it is advantageous than a continuous process.

5 show the mechanism for adto control the position of the i n respect to the film. On the slide 38 there is a dovetailed S. with a base rec by another dove-tailed slide connection idE, best shown in Figure 6. The base its is connected with the frame 88 by screws N34.

The knob 2 (Fig. 5) is held against endwise displacement by thrust hearings on a lug I08 much is fixed to the base H09. A lead screw I58 :3 connected with the knob and threads into e under slide Thus, rotation of the knob AS the lead screw I63 and causes the under to move up or down along its doveconnection to the base we depending direction of rotation of the knob 84.

e has a lug I l2 through which nob and there is a hearing element e 6) extending upward from the under slide 9% and provided with thrust bearings for preven endwise movement of knob and i s screw H3 with respect to the slide Thus rotation of the knob 85 reicrred embodiment of this invention has been illust ated and described, but changes and modifications can be made, and some features of the invention can be used alone or in diifer n combinations without departing from t invention as defined in the claims.

the film passing across said guide, a tray from which liquid developer is supplied to the peripheral portion of the dish, and means for adjusting the relative position of the shaft and film guide to control the area of the film to which the developer is applied by the disk.

2. Apparatus for treating the sound track along one side of colored motion picture film including a developer station, a guide roller rotatable about an axis and around which the film passes at the developer station, said guide roller having a sloping axis of rotation that maintains the film with its sound track side at the bottom of the slope, an applicator disk having a pointed peripheral edge, a bearing from which the applicator disk is supported for rotation about an axis extending at an acute angle to the axis of rotation of the guide roller, the applicator disk being so positioned with respect to the guide roller that the pointed portion of the applicator disk is adjacent to the blend line between the sound track and thing around the gui 3. Apparatus ound track of 0 ng a developer station, a guide roller at the dceloper station around which the film passes vith continuous motion, bearing on which the guide roller rotates about a sloping axis which d'sposes the guide roller in such position that the p acute angle to the oper station and the dge of the film that is nearer to the sound track is at the bottom of he slope, an applicator disg. supported for rota on about an axis at an acute angle to the iris oi the guide roller, a tray in vhich a developer is contained, the tray being at such a location that the lower portion of the applicator disk dips into the developer in the tray, said applicator disk being in such relation to the guide roller and "a that the upper portion of he applicato' es developer to the sound rack across the lull width of the sound track.

Apparatus for developing the sound track, only the sound tra of color-ea motion picture film, said apparatus comprising a developer station, a tray at the developer station for holding developer, a guide roller rotatable about an axis at an angle of the order of 35 to the horizontal, an applicator located between the guide roller nd t e a bearing on which the applicator disk rtates about an axis at an acute angle to the axis of the guide roller, the lower portion of the applicator disk extending downward into the tray and below the intended level of the developer in the tray, and the upper end of the applicator disk having its peripheral portion adjacent to the sound track of a film passing around the guide roller when the film is on the guide roller with the edge of the film that is nearer to the sound track at the bottom of the transverse slope of the film so that developer adheres to the peripheral portion of the applicator disk and is carried upward into contact with the sound track when the applicator disk rotates on its bearing.

5. Apparatus for developing the sound track, and only the sound track, of a colored motion picture film, said apparatus comprising a guide means around which a film passes at a developer station with the film having a transverse downward slope and the sound track nearer to the lowermost edge of the film, an applicator disk in position to apply a band of developer to the sound track of a film passing said guide means,

said disk having a peripheral portion that is located closer to the blend line edge of the sound track than to the other edge, and apparatus for supplying controlled amounts of developer to the peripheral portion of the applicator disk.

6. Apparatus for applying developer to the sound track and only the sound track of a col ored motion picture film including, in combination, guide means around which the film passes at a developer station with the film having a transverse downward slope and the sound track nearer to the lowermost edge of the film, an applicator disk that has a peripheral portion that extends adjacent to the sound track and that approaches nearest to the sound track along the blend line between the sound track and the picture areas of the film, means that supply developer to the peripheral portion of the applicator disk, apparatus that adjusts the disk toward and from the film guide means so as to maintain at least some clearance between the applicator disk and the film at the point of closest spacing of the disk from the film, and a motor operatively connected with the disk for rotating the disk at a controlled speed which determines the centrifugal force for moving the developer on the disk into contact with the film as the disk rotates.

7. Apparatus for treating the sound track of colored motion picture film comprising a guide around which a film passes at a developer station with the film having a transverse downward slope and the sound track nearer to the lowermost edge of the film, an applicator disk having front and back surfaces and a tapered peripheral face extending axially across substan- V tially the full width of the distance between the front and back surfaces of the disk to provide a pointed peripheral edge, bearing means supporting the applicator disk and on which it rotates about its axis, said bearing means supporting the disk with the pointed peripheral edge of the disk closely adjacent to the blend line between the sound track and the picture areas of a film passing around the film guide, means supplying a liquid developer to the peripheral portion of the applicator disk, means for controlling the liquid covering the pointed edge of the disk in the region of the film, said means comprising a motor that rotates the disk at a controlled speed, and a wiper located in position to remove excess developer solution from the sides of the disk, along that portion of the disk approaching the film, as the disk rotates.

8. Apparatus for developing the sound track of a colored motion picture film that has been bleached to convert the metal of the emulsion back to metal salt, said apparatus including a tray, a disk that dips into the tray, an inverted reservoir for supplying developer solution to the tray, said reservoir having an air vent at the desired liquid level in the tray for admitting air into the upper portion of the reservoir whenever the liquid level in the tray drops below the air vent, motor means for rotating the disk, a device for adjusting the speed of the motor to control the centrifugal force urging the developer solution toward the periphery of the disk as the disk rotates, a scraper for removing excess liquid from the portion of the disk moving upward from the liquid level in the tray, guide means around which film passes with the film having a transverse downward slope and the sound track nearer to the lowermost edge of the film, said guide means being located in such position with respect to the disk that the disk has a portion of its periphery adjacent to the sound track of the film for transferring developer to the sound track, and only the sound track, of the film passing around guide means.

9. Apparatus for developing the sound track, and only the sound track, of colored motion picture film, said apparatus comprising a developer station, a squeegee ahead of the developer station for moving loose water from the surface of the film, a first applicator disk at the developer station, a shaft supporting the applicator disk for rotation about an axis, a liquid tray in which the lower end of the applicator disk is immersed, a film guide that holds a film with a transverse downward slope of the film and with its sound track nearer to the lower edge of the film and adjacent to the upper edge of the applicator disk as the film travels through the developer station, a second applicator disk beyond the first applicator disk in the direction of film movement, a second tray in which the lower end of the second applicator disk is immersed, said film guide having a portion that holds the film with its sound track adjacent to the second applicator disk, separate reservoirs for supplying developer solution to the two trays one of said reservoirs maintaining a supply of more viscous developer solution in the first tray than in the second, and means for washing the developer solution from the film at a region beyond the developer station, the washing means including a nozzle that directs a jet of water across the sound track away from the blend line between the sound track and the picture areas of the film.

10. The apparatus for treating a sound track of a colored motion picture film as described in claim 1, and in which the guide means comprises a roller having peripheral surfaces that support the film on both sides of the sound track, and the guide roller has its surface spaced from the film at the region under the sound track.

ARTHUR J. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,986,107 Heisler Jan. 1, 1935 1,987,062 Hickman Jan. 8, 1935 2,143,787 Mannes et a1 Jan. 10, 1939 2,330,796 Bennes Oct. 5, 1943 

